1. Product Introduction
1.1 What is an ORP sensor?
An ORP sensor reflects the oxidizing or reducing capacity of water by capturing changes in redox potential, providing accurate data support for process control, water quality assessment, and pollution treatment.
1.2 What are the advantages of the KWS series ORP sensors?
Traditional ORP sensors commonly suffer from short electrode lifespan, weak anti-interference capability, inconvenient installation, and the need for frequent calibration. For example, ordinary industrial electrodes often need to be replaced within just a few months under harsh working conditions, which not only increases maintenance costs but also affects monitoring continuity. In industrial environments, electromagnetic interference can easily cause data distortion in conventional sensors, making them unreliable.
The KWS series ORP sensors have been comprehensively optimized and upgraded. They use durable ORP electrodes, with internal reference solution maintained under a pressure of at least 100 kPa (1 bar). The leakage rate through the microporous salt bridge is extremely slow, and the forward leakage can last for more than 20 months, greatly reducing maintenance costs and replacement frequency.
At the same time, the sensors are equipped with dual high-impedance differential amplifiers, providing strong anti-interference capability. Even in complex industrial electromagnetic environments, they ensure stable and accurate data with faster response, enabling timely detection of subtle changes in water potential.
In terms of installation, the KWS series ORP sensors adopt a 3/4 NPT pipe thread design, compatible with various installation scenarios and reducing construction difficulty. Some models also feature a built-in temperature sensor for automatic temperature compensation, further improving measurement accuracy and reducing errors caused by temperature fluctuations. This minimizes the need for frequent calibration and reduces manual maintenance workload.
2. KWS Series ORP Sensor Parameter Comparison
| Model | KWS-500A | KWS-500B | KWS-550 |
| Measuring Range | -1999 mV ~ 1999 mV | -1500 mV ~ 1500 mV | |
| Accuracy | ±20 mV | ±6 mV | |
| Resolution | 1 mV | 1 mV | |
| Operating Temperature | 0 ~ 50 °C | 0 ~ 65 °C | |
| Working Pressure | < 3 bar | < 0.1 MPa | |
| Output | RS-485 MODBUS | RS-485, MODBUS protocol | |
| Installation Method | Immersion installation 3/4 NPT | Used with multiparameter sensors | Immersion installation 3/4 NPT |
| Power Supply | 12 ~ 24 VDC | 12 ~ 24 VDC | |
| Material | POM + Titanium | POM | |
| Cable Length | 10 m, customizable | 5 m, customizable | |
| Calibration Method | One-point calibration | One-point calibration | |
| Protection Grade | IP68 | IP68 | |
3. Interpretation of Core Parameters
| Parameter | Parameter Meaning | Applicable Scenario Description |
| Measuring Range | Refers to the potential value range that the ORP sensor can accurately measure. Negative values represent reducing environments, while positive values represent oxidizing environments. | Around -400: anaerobic tanks in wastewater treatment Around +350: swimming pool disinfection |
| Accuracy | Indicates the deviation between the measured value and the true value. Higher accuracy means more reliable data. | High accuracy: medical, drinking water, food industries. Standard accuracy: industrial, surface water, aquaculture. |
| Output | The method by which the sensor transmits measured data to other devices. | RS485 is commonly used in industrial applications, offering long transmission distance and strong anti-interference capability, facilitating centralized data management and remote monitoring. |
4. Step-by-Step Selection Process
Step 1: Define application scenario and core requirements
● First, determine the specific application scenario of the ORP sensor (e.g., water quality monitoring, industrial wastewater).
● Clarify the core requirements for this scenario, such as measuring range, accuracy, temperature, and pressure parameters.
Step 2: Confirm output and power supply requirements
● Confirm the sensor output method based on your data acquisition needs.
● Verify whether the on-site power supply can meet the sensor’s requirements.
Step 3: Confirm installation and accessories
● Consider whether the sensor installation method meets on-site installation conditions.
● Check the distance between the sensor installation location and the control system. Cable length is customizable for all models. If the installation distance is long, contact us to customize the cable length to avoid insufficient cable length.
Step 4: Consult professionals
● If you are still unsure about the selection, you can consult the KACISE professional technical team. They will provide more targeted recommendations based on your specific requirements and site conditions.
5. Typical Application Scenarios
| Application Field | Recommended Model | Reason for Recommendation |
| Drinking water, food industry | KWS-550 | These scenarios require high ORP standards, demanding high resolution and high accuracy monitoring. |
| Industrial wastewater, aquaculture | KWS-500 | An accuracy of 20mV is sufficient for these fields. In addition, the KWS-500 offers a maximum range of up to 2000mV, providing a wider data range. |


6. Summary
To help you quickly identify the appropriate KWS series ORP sensor, we briefly review the key points of this guide: by comparing KWS series product parameters, you can initially filter models based on measurement range and accuracy requirements; understanding the meaning of core parameters helps match the most suitable application scenarios; finally, following the selection process can help avoid selection errors. The typical application scenario table provides direct references for common fields, enabling you to quickly find the recommended model.
If you still have questions about sensor selection or need customized solutions based on specific measurement requirements, feel free to contact us directly—our professional team will provide one-on-one guidance to help you choose the most cost-effective ORP sensor.
If you are unsure which model to choose, feel free to contact us with your application details for technical support.
